Caching Matrix Representations of Repeated Quantum Gates

Abstract

Replacing a sequence of gates with a replacement matrix. A quantum circuit may include a series of gates that includes a sequence of gates that is repeated within the series or in the quantum circuit. The sequence of gates is computed to generate a replacement matrix. The sequence of gates is then replaced with the replacement matrix. The replacement matrix improves performance by reducing the number of operations that would otherwise be required. The replacement matrix can be cached and allows the circuit to be executed locally, remotely, or both. The cached replacement matrix can be used in other quantum circuits that include the same sequence of gates represented by the replacement matrix.

What is claimed is: 
     
         1 . A method comprising:
 identifying a sequence of gates in a quantum circuit that repeats in a series of gates associated with a quantum circuit;   generating a replacement matrix for the sequence of gates;   replacing each instance of the sequence of gates in the quantum circuit with the replacement matrix; and   executing the quantum circuit that includes one or more instances of the replacement matrix.   
     
     
         2 . The method of  claim 1 , further comprising creating a custom gate, wherein the custom gate defines the series of gates that includes the sequence of gates. 
     
     
         3 . The method of  claim 1 , further comprising generating the replacement matrix by computing matrices included in the sequence of gates. 
     
     
         4 . The method of  claim 1 , further comprising caching the replacement matrix in local resources and/or remotely in execution resources and/or caching the series of gates after replacing the sequence of gates with the replacement matrix. 
     
     
         5 . The method of  claim 4 , further comprising executing a portion of the quantum circuit in the local resources and executing a portion of the quantum circuit in the execution resources associated with a quantum provider. 
     
     
         6 . The method of  claim 5 , further comprising replacing a sequence of gates in a second quantum circuit with the replacement matrix. 
     
     
         7 . The method of  claim 1 , further comprising paring the replacement matrix. 
     
     
         8 . The method of  claim 1 , further comprising applying a permutation matrix to the replacement matrix and using a resultant matrix with qubits in a different order. 
     
     
         9 . The method of  claim 1 , wherein the replacement matrix is computed a single time and wherein the replacement matrix is configured to reduce a number of matrix-matrix operations. 
     
     
         10 . The method of  claim 1 , further comprising storing the replacement matrix in a cache and associating the replacement matrix with the sequence of gates. 
     
     
         11 . A non-transitory storage medium having stored therein instructions that are executable by one or more hardware processors to perform operations comprising:
 identifying a sequence of gates in a quantum circuit that repeats in a series of gates associated with a quantum circuit;   generating a replacement matrix for the sequence of gates;   replacing each instance of the sequence of gates in the quantum circuit with the replacement matrix; and   executing the quantum circuit that includes one or more instances of the replacement matrix.   
     
     
         12 . The non-transitory storage medium of  claim 11 , further comprising creating a custom gate, wherein the custom gate defines the series of gates that includes the sequence of gates. 
     
     
         13 . The non-transitory storage medium of  claim 11 , further comprising generating the replacement matrix by computing matrices included in the sequence of gates. 
     
     
         14 . The non-transitory storage medium of  claim 11 , further comprising caching the replacement matrix in local resources and/or remotely in execution resources and/or caching the series of gates after replacing the sequence of gates with the replacement matrix. 
     
     
         15 . The non-transitory storage medium of  claim 14 , further comprising executing a portion of the quantum circuit in the local resources and executing a portion of the quantum circuit in the execution resources associated with a quantum provider. 
     
     
         16 . The non-transitory storage medium of  claim 15 , further comprising replacing a sequence of gates in a second quantum circuit with the replacement matrix. 
     
     
         17 . The non-transitory storage medium of  claim 11 , further comprising paring the replacement matrix. 
     
     
         18 . The non-transitory storage medium of  claim 11 , further comprising applying a permutation matrix to the replacement matrix and using a resultant matrix with qubits in a different order. 
     
     
         19 . The non-transitory storage medium of  claim 11 , wherein the replacement matrix is computed a single time and wherein the replacement matrix is configured to reduce a number of matrix-matrix operations. 
     
     
         20 . The non-transitory storage medium of  claim 11 , further comprising storing the replacement matrix in a cache and associating the replacement matrix with the sequence of gates.